The acetylcholinesterase gene Ace: A diagnostic marker for the Pipiens andQuinquefasciatus forms of the Culex pipiens complex

The taxonomy of the Culex pipiens complex remains a controversial issue in mosquito systematics. Based on morphologic characters, 2 allopatric taxa ar e recognized, namely Cx. pipiens (including the form "molestus") in tempera te areas and Cx. quinquefasciatus in tropical areas. Here we report on vari ability at the nucleotide level of an acetylcholinesterase gene in several strains and natural populations of this species complex. Few polymorphisms were found in coding regions within a subspecies but many polymorphisms wer e observed between subspecies in noncoding regions. We describe a method ba sed on a restriction enzyme polymorphism in polymerase chain reaction-ampli fied DNA, in which the presence or absence of one restriction site discrimi nates Cx. pipiens, Cx. quinquefasciatus, and their hybrids. This technique reliably discriminates mosquitoes from more than 30 worldwide strains or po pulations. Polymerase chain reaction amplification of specific alleles may also be a useful tool for characterizing specific alleles of each sibling t axon.